Sliding members for use typically as automotive engine parts require excellent abrasion resistance and slidability. To impart these properties, coating of a sliding member on its surface with a hard coating such as a diamond-like carbon film (DLC film) has been performed. Typically, Patent Literature (PTL) 1 discloses coating of a sliding member on its sliding surface with a film. This film includes two diamond-like carbon layers differing from each other in hardness, Young's modulus, and thickness. PTL 1 describes that the resulting sliding member exhibits two properties, i.e., durability and low frictional coefficient.
PTL 2 discloses formation of a nitrogen-containing amorphous carbon film on a sliding surface of a sliding member. This film contains hydrogen of from 8.0 to 12.0 atomic percent and nitrogen of from 3.0 to 14.0 atomic percent. PTL 2 describes that the sliding member bearing the film exhibits satisfactory durability even when used under a high surface pressure or in an oil lubrication environment.